Although children don’t yet understand what words mean, they may stop doing something when a parent or caregiver says “no.” Even if they stop, this does not mean that they understand that something they are doing is wrong or that they have learned that certain behavior is unacceptable. They might try the same thing again later, and this normal response shows a healthy desire to explore.
Shelov, S. P. (Editor-in-Chief). (2004). Caring for Your Baby and Young Child: Birth to Age 5. The American Association of Pediatrics. Revised edition. New York: Bantam Books.